JP2005086906A - Method of stating variable speed generator-motor, and controller for variable speed generator-motor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To materialize a quick start by solving a conventional problem such as that a control circuit becomes complicated because there is necessity to perform intermittent control and phase detecting operation at the initial stage of the start. <P>SOLUTION: In the state that a primary winding 1a is cut off from a power system 8 and also the primary winding 1a is short-circuited in three phases, a secondary winding 1b is supplied with power to start a generator-motor, and when it reaches a specified rotation state, the excitation of the secondary winding 1b is stopped, and also the three-phase short circuit of the primary winding 1a is opened, and the primary winding 1a is supplied with power, and the excitation of the secondary winding 1b is started again with DC or three-phase AC of constant low frequency. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a variable speed generator motor starting method and a variable speed generator motor control device.

  In general, in order to start a large-capacity synchronous generator motor as a motor, another starter is required, and a thyristor starter is widely applied as a starter. The thyristor starting device is a frequency converter composed of a converter and an inverter using a thyristor, and generates a rotating magnetic field from zero to a commercial frequency in the primary winding of the generator motor to start the generator motor. The variable speed generator motor is basically the same as described above, and the thyristor starter generates a rotating magnetic field in the primary winding while the secondary winding is excited by direct current excitation or constant low frequency. Such a technique is known, for example, in JP-A-8-80094.

  In the initial stage of starting with this starting method, since the induced voltage generated by the generator motor is low and the thyristor of the inverter cannot be commutated, intermittent control is performed to make the converter current zero at the commutation timing.

  Further, since the ignition phase cannot be detected when the voltage of the generator motor is low, a position detector that mechanically detects the position of the rotor is provided. In the case of a synchronous machine, since the rotor magnetic pole is fixed, the position is detected by a tooth disk attached to the rotating shaft and a proximity switch, and the inverter thyristor is ignited.

  In the case of a variable speed generator motor, the magnetic pole generated in the rotor does not coincide with the mechanical position of the rotor, so the phase that the inverter should fire is calculated from the mechanical position detected by the resolver and the excitation phase. There is a need.

JP-A-8-80094

  In the conventional starting method, it is necessary to perform intermittent control and phase detection calculation in the initial stage of starting. For this reason, the control circuit is complicated, and the current is intermittent. Moreover, high accuracy is required for the ignition phase calculation at the start of the start, and even if it is slightly shifted, commutation failure and the like are caused. In addition, when the generator motor is inspected, the ignition phase calculation circuit must be adjusted, which requires maintenance man-hours such as requiring a controller technician in addition to the generator motor inspector.

  Furthermore, commutation may fail due to a slight change in the characteristics of the position detector, causing a problem in safety. An object of the present invention is to eliminate the need for intermittent control and phase detection calculation at the beginning of startup.

  In order to achieve the above object, according to the present invention, in the initial stage of starting, the primary winding of the variable speed generator motor is short-circuited in three phases, and the secondary winding is predetermined (desirably by an excitation frequency converter, for example). Is started by supplying power of a predetermined frequency), and when a predetermined rotational state is reached, the excitation to the secondary winding is stopped and for three-phase short-circuiting (for example, short-circuiting by operating the disconnector) Is opened, the primary winding is connected to a frequency converter (starting frequency converter), and the secondary winding is re-excited with DC or constant low-frequency three-phase AC, and the primary winding is A power is supplied from the starting frequency converter at a predetermined frequency.

  Alternatively, at the initial stage of startup, the frequency converter (preferably for starting and constituting the converter and inverter) is continuously ignited (elements are preferably all elements), and the primary winding of the generator motor (specifically As an example, with a three-phase short circuit condition (via a starting frequency converter), the secondary winding is started by supplying power (eg, from the excitation frequency converter) and reaches a predetermined rotation. Then, stop the element firing of the frequency converter (starting frequency converter) (elements are preferably all elements), stop the excitation to the secondary winding, and then the excitation of the secondary winding The generator motor is configured to be re-excited with direct current or three-phase alternating current at a constant low frequency and supplied with electric power of a predetermined frequency from the starting frequency converter to the primary winding.

  Here, in order to understand the above configuration, the operation of a specific example will be described. In the initial stage of startup, with the primary winding of the variable speed generator motor short-circuited in three phases, the secondary winding is started by supplying power at a predetermined frequency from the excitation frequency converter. The excitation to the secondary winding is stopped, the disconnector for the three-phase short circuit is opened, the primary winding is connected to the starting frequency converter, and the secondary winding is excited for direct current or constant low frequency The generator motor is started by re-excitation with phase alternating current and supplying power of a predetermined frequency to the primary winding from the starting frequency converter. Intermittent control and position detection calculations required at the beginning of the start are not required, the control device is simplified, and maintenance costs can be reduced.

  Further, at the initial stage of starting, all elements constituting the converter and inverter of the starting frequency converter are continuously ignited, and the primary winding of the generator motor is short-circuited through the starting frequency converter. Then, power of a predetermined frequency is supplied to the secondary winding from the excitation frequency converter. When the specified rotation is reached, all the elements of the starting frequency converter are ignited, and the excitation to the secondary winding is stopped. The generator motor is started by re-exciting with alternating current and supplying electric power of a predetermined frequency to the primary winding from the starting frequency converter. Intermittent control and position detection calculations required at the beginning of the start are not required, the control device is simplified, and maintenance costs can be reduced.

  As described above, according to the present invention, intermittent control and complicated ignition phase detection calculation are not required, and the apparatus can be simplified. Alternatively, adjustment of the phase detection calculation at the time of installation trial operation or the like becomes unnecessary, and the man-hour can be reduced. Alternatively, adjustment of phase detection is not necessary, and maintenance costs can be reduced. Alternatively, the commutation failure due to the characteristic change of the phase detection is eliminated, and the safety is improved.

  Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 shows an embodiment of a variable speed pumped storage power generation system to which the present invention is applied. In FIG. 1, the primary winding 1 a of the variable speed generator-motor 1 is connected to a power system 8 via a parallel circuit breaker 6 and a phase inversion disconnector 7. The secondary winding 1b of the variable speed generator-motor 1 is connected to the power system 8 via the excitation frequency converter 2, the excitation transformer 9, and the excitation circuit breaker 10 controlled by the excitation control device 3. The frequency converter 2 supplies three-phase AC power to the secondary winding 1b of the variable speed generator motor 1.

On the other hand, the primary winding 1a of the variable speed generator-motor 1 is connected to the start frequency converter 4 controlled by the start control device 5 via the start disconnectors 11 and 12 and the start breaker 13. The starting frequency converter 4 includes a thyristor converter (or a converter for the starting frequency converter; the same applies hereinafter) 4a, a thyristor inverter (or a converter for the starting frequency converter; the same applies hereinafter) 4b, and a DC reactor 4c. It is configured, and is connected to the power system 8 via the starting transformer 14 and the starting input circuit breaker 16. The starting frequency converter 4 supplies AC power to the primary winding 1a of the variable speed generator motor 1 in a state where the parallel circuit breaker 6 is opened, and starts the variable speed generator motor 1.

Here, since the induced voltage of the generator motor 1 is low and the thyristor inverter 4b cannot commutate in the low rotation region at the beginning of the start, the converter 4a is gate-shifted in accordance with the ignition timing of the inverter 4b to reduce the current to zero. Then, intermittent control is performed in which the commutation is performed by passing the current again, and in the region where the induced voltage of the generator motor 1 is low, the voltage phase for starting the inverter 4b cannot be detected. The device 3 calculates the phase to be ignited by the inverter 4b from the mechanical position of the rotor detected by the resolver 15 and the excitation phase, and outputs it to the start control device 5, whereby the inverter 4b is ignited. On the other hand, it is desirable to omit complicated intermittent control and phase detection calculation at the initial stage of starting. The specific configuration will be described below.

  When the variable speed generator-motor 1 short-circuits the primary winding 1a and supplies AC power with a predetermined frequency from the excitation frequency converter 2, an induction torque is generated and rotates. However, in this case, in order to increase the rotation to near the system frequency, the capacity of the excitation frequency converter 2 is increased, and the starter frequency converter 4 is used to start another synchronous machine in the pumped storage power plant. Therefore, the starting frequency converter 4 cannot be eliminated, and this starting method is not general. However, although acceleration cannot be performed up to the vicinity of the system frequency, it is possible to start to a rotation that does not require intermittent control and position detection calculation of the starter, and therefore this control method can omit intermittent control and phase detection calculation.

  The starting method according to the first embodiment will be specifically described below (particularly related to claim 1 of the present application). In FIG. 1, first, the three-phase short circuit disconnector 17 for short-circuiting the primary winding 1 a of the variable speed generator-motor 1 is closed, and the secondary winding 1 b of the variable speed generator-motor 1 is connected to the direct current from the excitation frequency converter 2. Excited. Next, when the excitation frequency is gradually increased, the variable speed generator-motor 1 starts to rotate due to the induction torque. When the speed is accelerated to an unnecessary speed, for example, about 8 Hz, by this method, the output of the excitation frequency converter 2 is stopped once, the three-phase short-circuit disconnecting switch 17 is opened and the starting disconnecting switches 11 and 12 are started. The circuit breaker 13 is closed, and the excitation frequency converter 2 is again excited with direct current or a constant low frequency alternating current, and the starting frequency converter 4 is operated. Thereafter, the starting frequency converter 4 can accelerate the variable speed generator motor 1 to a speed at which the variable speed generator motor 1 can be parallel to the power system. Note that the switching speed needs to be determined in consideration of the decrease in speed during circuit switching. In addition, switching circuit operation, excitation stop and re-excitation operations must be performed as quickly as possible.

Next, a starting method according to the second embodiment will be described (particularly related to claim 5). This is a method in which the primary winding 1a of the variable speed generator motor 1 is short-circuited by using the starting frequency converter 4 when the three-phase short-circuit disconnecting switch 17 is not provided. In FIG. 1, first, the starter circuit breaker 13 and the starter disconnectors 11 and 12 are closed, and the starter input circuit breaker 16 is opened, the converter (converter) 4a of the starter frequency converter 4, the inverter (reverse) All elements of the converter 4b are fired continuously. Thus, the primary winding 1a of the variable speed generator-motor 1 is short-circuited through the DC reactor 4c. In this state, the secondary winding 1b of the variable speed generator motor 1 is DC-excited from the excitation frequency converter 2. Next, when the excitation frequency is gradually increased, the variable speed generator-motor 1 starts rotating due to the induction torque. When the speed is accelerated to an unnecessary speed, for example, about 8 Hz, by this method, the output of the excitation frequency converter 2 is stopped once and the ignition of the start frequency converter 4 is stopped. When the current becomes zero, the starter input circuit breaker 16 is closed, and the excitation frequency converter 2 is again excited with direct current or a constant low frequency alternating current, and the start frequency converter 4 is normally operated. Thereafter, the starting frequency converter 4 can accelerate the variable speed generator motor 1 to a speed at which the variable speed generator motor 1 can be parallel to the power system. Note that the switching speed needs to be determined in consideration of the decrease in speed during circuit switching. However, in this method, since there is no operation of the disconnector and the circuit breaker, the switching speed is shorter than that in the first embodiment. Switching is possible. By starting in this way, the intermittent control and the complicated ignition phase detection calculation conventionally required at the beginning of the start become unnecessary, and the start control device 5 and the excitation control device 3 can be simplified.

  As described above, according to the present embodiment, the intermittent control and the complicated ignition phase detection calculation that are conventionally required at the beginning of the start are not required, and the start control device 5 and the excitation control device 3 can be simplified. This eliminates the need for adjustment of the phase detection calculation at the time of installation trial operation, etc., thereby reducing man-hours. In addition, during maintenance of the generator motor, adjustment of phase detection, which has been necessary in the past, becomes unnecessary, and maintenance costs can be reduced. Furthermore, commutation failure due to a characteristic change of phase detection is eliminated, and safety is improved.

1 is a configuration diagram of a variable speed generator motor and a starter thereof according to an embodiment of the present invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Variable speed generator motor, 1a ... Primary winding of variable speed generator motor, lb ... Rotor and secondary winding of variable speed generator motor, 2 ... Frequency converter for excitation, 3 ... Excitation control device, 4 ... Start Frequency converter for use, 4a ... Converter for start-up frequency converter, 4b ... Inverter for start-up frequency converter, 4c ... DC reactor for start-up frequency converter, 5 ... Start control device, 6 ... Parallel breaker, 7 ... Phase reversal disconnector, 8 ... Power system, 9 ... Excitation transformer, 10 ... Excitation breaker, 11 ... Start disconnector (generator side), 12 ... Start disconnector (starter side), 13 ... Circuit breaker for starting,
14 ... Starter transformer, 15 ... Resolver, 16 ... Starter input circuit breaker, 17 ... Three-phase short-circuit disconnector.

Claims (10)

  In the state where the primary winding of the variable speed generator motor is disconnected from the power system and the primary winding of the variable speed generator motor is short-circuited in three phases, power is supplied to the secondary winding of the variable speed generator motor. When the variable speed generator-motor is started and the variable-speed generator-motor reaches a predetermined rotational state, excitation to the secondary winding of the variable-speed generator-motor is stopped and the primary winding of the variable-speed generator-motor Open the three-phase short circuit, supply power to the primary winding of the variable speed generator-motor, and re-excite the secondary winding of the variable-speed generator motor with direct current or three-phase alternating current at a constant low frequency. A variable speed generator motor starting method for starting a variable speed generator motor by means of the above.   The electric power is supplied to the primary winding from a frequency converter according to claim 1, and the three-phase short circuit operates electrical continuity between the secondary winding and the frequency converter by a disconnector. The variable speed generator motor starting method made in.   3. The variable speed generator motor starting method according to claim 2, wherein the frequency converter includes a converter and an inverter.   The variable speed generator according to any one of claims 1 to 3, wherein the primary winding of the variable speed generator motor is disconnected from the power system by operating electrical continuity between the power system and the primary winding by a circuit breaker. Generator motor starting method.   The primary winding of the variable speed generator motor is disconnected from the power system, and a plurality of elements constituting a frequency converter that supplies power to the primary winding of the variable speed generator motor are continuously ignited, With the primary winding of the generator motor short-circuited in three phases, the variable speed generator motor is started by supplying predetermined power from the frequency converter to the secondary winding of the variable speed generator motor. When the variable speed generator motor reaches a predetermined rotation, the frequency converter is stopped from firing and the excitation to the secondary winding of the variable speed generator motor is stopped, and then the secondary of the variable speed generator motor is stopped. The variable-speed generator motor is started by re-exciting the excitation of the winding with direct current or three-phase alternating current of constant low frequency, and supplying power of a predetermined frequency from the frequency converter to the primary winding of the variable-speed generator motor. Variable speed generator Machine starting method.   6. The variable speed generator motor starting method according to claim 5, wherein the three-phase short circuit is performed by operating electrical conduction between the secondary winding and the frequency converter with a disconnector.   6. The variable speed generator motor starting method according to claim 5, wherein the frequency converter includes a converter and an inverter.   The variable speed generator according to any one of claims 6 to 8, wherein the primary winding of the variable speed generator motor is disconnected from the power system by operating electrical conduction between the power system and the primary winding by a circuit breaker. Generator motor starting method.   In a control device for a variable speed generator motor that controls power supplied to a primary winding and a secondary winding of a variable speed generator motor to start the variable speed generator motor, the primary winding of the variable speed generator motor is connected to a power system. In the state where the primary winding of the variable speed generator motor is short-circuited in three phases, power is supplied to the secondary winding of the variable speed generator motor to start the variable speed generator motor, and When the variable speed generator motor reaches a predetermined rotational state, the excitation to the secondary winding of the variable speed generator motor is stopped, the three-phase short circuit of the primary winding of the variable speed generator motor is opened, and the variable speed generator motor is opened. Power is supplied to the primary winding of the generator motor, and the variable speed generator motor is started by re-exciting the secondary winding of the variable speed generator motor with direct current or three-phase alternating current at a constant low frequency. Variable speed departure The control device of the electric motor. In the control device for a variable speed generator motor that controls the power supplied to the primary winding and the secondary winding of the variable speed generator motor to start the variable speed generator motor, the power is supplied to the primary winding of the variable speed generator motor. A frequency converter to supply, disconnecting the primary winding of the variable speed generator motor from the power system, and continuously igniting a plurality of elements of the variable speed generator motor, the primary of the variable speed generator motor The variable speed generator motor is started by supplying predetermined power from the frequency converter to the secondary winding of the variable speed generator motor in a state where the windings are three-phase short-circuited. When the predetermined rotation is reached, the ignition of the frequency converter is stopped and the excitation to the secondary winding of the variable speed generator motor is stopped, and then the secondary winding of the variable speed generator motor is excited. DC or constant A variable speed generator-motor, which is re-excited by a three-phase AC frequency and starts the variable-speed generator motor by supplying electric power of a predetermined frequency from the frequency converter to the primary winding of the variable-speed generator motor Control device.

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